Within the framework of several local and international programs, a quasi-operational ocean-forecasting system for the Southeastern Mediterranean Sea has been established and evaluated through a series of preoperational tests. The Princeton Ocean Model (POM) is used for simulating and predicting the hydrodynamics while the Wave Model (WAM) is used for predicting surface waves. Both models were set up to allow varying resolution and multiple nesting. In addition, POM was set up to be easily relocatable to allow rapid deployment of the model for any region of interest within the Mediterranean Sea. A common requirement for both models is the need for atmospheric forcing. Both models require time varying wind or wind stress. In addition, the hydrodynamic model requires initial conditions as well as time dependent surface heat fluxes, fresh water flux, and lateral boundary conditions at the open boundaries. Several sources of atmospheric forcing have been assessed based on their availability and their impact on the quality of the ocean models' forecasts. The various sources include operational forecast centers, other research centers, as well as running an in-house regional atmospheric model. For surface waves, higher spatial and temporal resolution of the winds plays a central role in improving the forecasts in terms of significant wave height and the timing of various high wave events. For the hydrodynamics, using the predicted wind stress and heat fluxes directly from an atmospheric model can potentially produce short range ocean forecasts that are nearly as good as hindcasts forced with gridded atmospheric analyses. Finally, a high-resolution, nested version of the model has shown to be stable under a variety of forcing conditions and time scales, thus indicating the robustness of the selected nesting strategy. For the southeastern corner of the Mediterranean, at forecast lead times of up to 4 days the high-resolution model shows improved skill over the coarser resolution driving model when compared to satellite derived sea surface temperatures. Most of the error appears to be due to the analysis error inherent in the initial conditions.
Bibliographical noteFunding Information:
The results presented here represent the combined efforts from several concurrent projects all of which have contributed to the establishment of our regional, operational forecasting system. We acknowledge the support received for various parts of this work from the European Union through three projects — MFSPP (Contract Number MAS3-CT98-0171), MFSTEP (Contract Number EVKT3-CT-2002-00075), and CYCLOPS (indirect partial support, Contract number EVK3-CT-1999-00009). Similarly, we thank the Ministry of Defense as well as the Ministry of National Infrastructures for their support through internal funding at IOLR. The ECMWF data were provided as part of MFSPP and the Hadera wave data were provided by IOLR. We would like to thank Dr. Henry Juang from NCEP and Drs. John Roads and Shyh Chen from the Experimental Climate Prediction Center (ECPC) at the Scripps Institution of Oceanography for their invaluable help in getting the RSM up and running. Finally we thank the two anonymous reviewers whose valuable comments helped us improve the manuscript.
- Atmospheric forcing
- Levantine Basin
- Mediterranean Sea
- Numerical ocean models
- Ocean forecasting
- Wave forecasting